Method of making incandescent mantles



March 12, 1935.f Y c. s. FRANCIS, JR 1,993,778

METHOD OF MAKING INCANDESCENT MANTLES I Filed Dec. s, 197,2l

ATTORNEYS Patented ar. l2, 1935 UNITED-STATE-s This invention relates tothe manufacture of incandescent mantles.

An object of my invention is to providea gas incandescent having superior properties to those `previously made. Otherobjects of this invention will appear from tion.

Incandescent or Welsbach mantles have been Apreviously madefbyimpregnating with suitable salts a knitted fabric made of cotton, natural silk the following detailed 'descrip- Y or of artificial silk of reconstituted cellulose prepared bythe `viscose -or similar methods. However when these -mantles are ignited to burn off the cellulose material, the ash `or incandescent 4material remaining' `is discolored. Furthermore,

such 'mantles Shrink f considerably after ignition `so that their distance from the-orifice of the` BunsenV or other-burner is varied, as is also the ratio of the area of the incandescent surface to the amount of heat applied, with the result that maximum efficiency is not attainable.

I have found that if Welsbach or other gas incandescents are made by impregnating a fabric made of saponied cellulose acetate or other organic ester of cellulose filaments or yarns with suitable salts or compounds of metals producing refractory and incandescent compounds, there may be produced in this manner incandescents having superior properties to those previously made. Among such advantages are that the ash or incandescent proper formed after ignition of the fabric is substantially free of color; Yand that when the mantle is ignited, it does not shrink so that the distance of the mantle from the orifice of the Bunsen burner is maintained constant and subject to exact control by the manufacturers, and theratio of the surface of the ignited mantle to the amount of heat applied by the burner is maintained constant,V with the result that maximum light-emitting efciency may be attained.

In accordance with my invention I prepare gas or other incandescents by `impregnating a fabric of suitable shape and made of yarns or filaments of a saponied organic ester of cellulose with salts or other compounds of the rare earth metals capable of forming refractory and incandescent compounds upon ignition.

Usually the incandescentmaterial `will be formed by impregnating a tubularknitted fabric Y made of the saponied organic ester of cellulose,

' but if desired fabric of other shape and either knitted, woven or netted may be employed.

The yarn employed as the starting material is made of filaments o f cellulose acetate or other organic ester of cellulose such as cellulose formate, cellulose Apropionate and cellulose butyrate. While I prefer to form a fabric of-the unsaponilied organicA ester of cellulose yarn and vthen saxponify the organic ester of cellulose' by treatment of the fabric with a-saponifying agent, if desired, the fabric may be made by knitting or otherwise associating together previously saponifled organic ester of cellulose yarn.

'Ihe unsaponied yarn employed may be of any suitable size vsay 150 to 440 denier, and inothe choice of the size of the unsaponied yarn employed, due regard should be given to the fact that upon saponiiication, the yarn suffersV an appreciable loss in weight so that if the' finished mantle is to be made of a yarn of a given denier, the unsaponified yarn employed as the starting #material Lwill be of correspondingly'higlier denier.

In order to saponify the cellulose acetate or other organic ester of cellulose in the knitted fabric or in the yarn used as the starting material, the same is treated with an aqueous, alcoholic or other suitable solution of an alkaline material of such amount and in such concentration as to cause the required degree o-f saponii'lcation. Examples of suitable alkaline materials are alkalies such as sodium hydroxide, potassium hydroxide or ammonium hydroxide;4 or alkaline salts such as sodium carbonate, potassium carbonate, sodium phenolate, potassium phenolate, sodium silicate, potassium silicate, sodium sulte, potassium sulte, trisodium phosphate, tripotassium phosphate, or mixtures of two or more of these. Saponication may also be caused by exposing the organic ester of cellulose material to the action of ammonia or other gaseous or vapor` o-us base in the presence of moisture. Y

To produce the incandescent, the fabric of saponied organic ester of cellulose` material is impregnated with any suitable compound or` salt of a metal capable of producing a refractory incandescent upon ignition; especially the salts of therare earths;` e. g. a mixture of thorium nitrate and cerium nitrate, in any known or suitable manner.

The accompanying drawing shows a gas mantle of conventional form illustrating one form of my invention.,

In order further to illustrate my invention but without being limited thereto the following example is given.

Example The cellulose acetate knitted fabric is saponied by immersing one part by Weight thereof in 50 parts by Weight of Water at 85 C. and contain' ing an amount of sodium hydroxide equal to 5% of the Weight of the goods for 20 minutes, after which 5 increments of further quantities of sodium hydroxide, each equal in Weight to of the Weight of the goods, are added at 10 minute intervals. After the addition of the last increment of sodium hydroxide, the goods are permitted to remain in the bath for 30 minutes.

The saponified material is then rinsed twice in soft Water and finally washed off in distilled water and dried.

The material is then impregnated in an aqueous solution of a mixture of thorium nitrate and cerium nitrate, theproportions of which are such that after ignition, the ash contains 98V to 99% of thorium oxide and 2 to 1%of cerium oxide.

After drying the tubular fabric is cut and shaped ,to the desired form such as is shown at 1 on the accompanying drawing. 25

The foregoing detailed description is given merely by Way of illustration and many variations may be made therein without departing from the Aspirit of my invention.

Having described my invention, what I desire to secure by Letters Patent is:

1., Method of preparing gas incandescents which .comprises immersing a fabric comprising an organic ester of cellulose in anaqueous bath containing an amount of alkali insuflicient to saponify completely the organic ester of cellulose,

Aadding further quantities of alkali in increments lto saponify the organic ester of cellulose further, ,and subsequently impregnating the saponied filaments of acetone-soluble cellulose having an `acetyl value of 54 to 55%.

fabric with compounds capable of forming a refractory incandescent upon ignition.

2. Method of preparing gas incandescents which comprises immersing a fabric comprising cellulose acetate in an aqueous bath containing an amount of alkali insufficient to saponify completely the cellulose acetate, adding further quantities of alkali rin increments to saponify the cellulose acetate further, and subsequently impregnating the saponied fabric with compounds capable of forming a refractory incandescent upon ignition.

3. Method of forming gas incandescents which comprises immersing a fabric comprising an organic ester of cellulose in an aqueous bath containing 5% of sodium hydroxide based `on the Weight 'of the fabric for 20 minutes, then adding to said bath at intervals of 10 minutes a further quantity of sodiumhydroxide equal in weight to 10% of the Weight of the fabric until ve such additions are made, permitting the fabric to relmain in said bath for 30 minutes and then, after the fabric is Washed and dried, impregnating the same with compounds capable of forming a refractory incandescent upon ignition. Y

4. Method of forming gas incandescents which comprises immersing a fabric comprising cellulose acetate in an aqueous bath containing 57% of .sodium hydroxide based on the weight of. the

fabric for 20 minutes, then adding to said bath at intervals of 10 minutes a further quantity of sodium hydroxide equal in Weight to 10% of the Weight of the fabric until five such additions are made, permitting the fabric to remain insaid bath for 30 minutes and then, after the fabric is Washed and dried, impregnating the same with compounds capable of forming a refractory incandescent upon ignition. I

i CARLETON S. FRANCIS, JR.

CERTIFICATE on mnnnmmn. "Pam Nn 1,993,778.

March 12, 193

CARLETON S. FRANCIS, JR. E is hereby certified that errar appears in the numbered paient requiring cnrrection a for Wil" ead 400; and

inn therein that me same may conform m t Patent Qafc.

Signed and sealed ms printed spacfczzon nf he a wh this ih day of April, A. D. i935.

Les l ie Frazer' (Snai) Acting Cn mmssonr of Patents'.

@Emme/@E m? @Mmmm mem N0. 1,993,778- mmh 12. H935. CARLETGN S. FRANCIS, JR.

' is hereby cerfied that errar appears in the prmd pecfcatem of the above numbered @ment requiring wrrecton as olmfvs: Page E, second commu, line EL for "fi-4?" read 400; and that the said Leiters Paem should he umd with fths @affection therein mt the same may ccnorm m ih@ moord of me @ase in the Pai'ent Qffice.

Sgned and sealed ms 16H1 day of AMM, A. D i935.

Leslie Frazer (Saai) Acimg' Commissvmer @f Paemsg 

